The pathology of human cardiac transplantation: an assessment after 11 years' experience at Groote Schuur Hospital.

Over a period of 11 years, commencing in December 1967, 31 cardiac transplants, 10 orthotopic and 21 heterotopic, were performed at Groote Schuur Hospital. Two patients with orthotopic transplants have a long survival, 1 for 7 1/2 and 1 for 9 1/2 years, and 1 with a heterotopic transplant for 4 years. Eighteen patients have died, and autopsy was performed from 13 to 623 days postoperatively. Rejection of the donor heart was found in 61,1% and was the cause of death in 44,4% of cases. Infection, attributable to immunosuppression, was a common finding and consisted of extensive pneumonia, usually due to Klebsiella aerogenes and Pseudomonas aeruginosa (38,8%), herpesvirus infection (38,8%), cytomegalic virus infection (37,5%), aspergillosis and other opportunistic infections. A combination of cardiac rejection and infection accounted for most of the deaths. The cardinal microscopic features of acute rejection were interstitial lymphocytic infiltration and myocytolysis, while chronic rejection was typified by obliterative myo-intimal proliferation of coronary arteries, with concurrent lipid deposition in the major coronary arteries. These lesions resembled atherosclerosis and caused graft failure due to myocardial ischaemia. Ultrastructurally, severe myofibre damage was reflected in extensive loss of cytoplasmic myofilaments. The advantages of heterotopic over orthotopic transplantation are discussed.